It is desirable to add fillers to polymer compositions to improve properties such as heat distortion temperatures, dimensional stability, and stiffness. However, this presents some problems. First, many fillers are not compatible with polymers, especially polyolefin polymers which tend to be highly non-polar. A further problem is that there is an increasing desire to use nanoparticles (less than 0.1 μm average particle diameter) to improve the performance of thin films and micro and nano-fibers made from polyolefins. Such nanoparticles have very high surface areas so they disperse even more poorly than larger particles.
Dispersing polar nanofillers in nonpolar polyolefins has always been challenging. Despite the theoretical promises of having a polyolefin nanocomposite with nano-dispersed silica clusters for enhancements in mechanical stiffness, strength, rheological melt strength, shear thinning, and in thermal heat distortion resistance, there are currently no polyolefin-silica nanocomposites commercially available. What is needed is a way to thoroughly disperse polar nanoparticles such as silica into a polyolefin (e.g., polyethylene and/or polypropylene) matrix. The present invention(s) is directed to such an end.
Related disclosures include U.S. Pat. Nos. 8,840,996; 8,669,326; 5,229,022; US 2014/088264; US 2014/275433; US 2009/0318644; WO 2004/024800; WO 2009/155517; WO 2009/155510; WO 2009/155471; WO 2009/155472; WO 2013/041151; Gelest Inc., “Silane Coupling Agents: Connecting Across Boundaries” (2006); and U.S. Ser. No. 61/866,702, filed Aug. 16, 2013.